Over the relatively recent past, the marketplace has witnessed a considerable consumer interest in citizens band (CB) radios suited for use in both pleasure and commerical vehicles. For adequate performance, these radios require an antenna of relatively elongate configuration, (i.e. from 2 to 9 feet in length) which is mounted upon an external surface of the vehicle. For more improved or optimised radio performance the aerials or antennae preferably are mounted at a higher position on the vehicle, for example, upon the roof or upward side portion of an automobile or truck to achieve a directional pattern that is roughly an oval. Additionally, inasmuch as the larger antenna (9 feet) represents an even fraction of a 27-MH.sub.z Citizens Band (CB) wave, its efficiency and the consequent desirability of its use becomes apparent.
However, when so mounted for optimised reception and transmission, the antennae, the longer of which are referred to as "whip antennas," extend a considerable distance above the roadway. So positioned they are in jeopardy of striking overhead elements such as trees, overhead bridge structures, building entrance ways and the like which are typically encountered in day-to-day driving. One approach to avoiding these potentially damaging obstructions is to mount the antenna at a lower position on the vehicle. However such safer mounting positions will engender less desirable radio performance. Techniques have been proposed in the past for automatically or semi-automatically selectively elevating or lowering vehicle mounted antennae. For instance, reference is made to U.S. Pat. Nos. 3,143,646; 2,949,608 and 2,933,597 wherein automobile mounted antennae are driven by an electric motor to an operational position upon the switching on of a radio mounted within the passenger compartment thereof. Generally, these approaches to antenna elevation are concerned with more conventional antenna structures of a telescoping variety. To derive the logic necessary to provide energization of the antenna drive motor both during and subsequent to the switching on of power to the radio, the patents look exclusively to that circuit logic which is available through the use of electro-magnetic relays, for instance solenoid actuated switches and the like. Disadvantage accrues with the use of such components and logic, particularly, by virtue of the necessary complexity of the resultant elevating device and consequent cost to the consumer. Further, such techniques for achieving a desired automatic elevation of the antennae do not provide for a desirable apprisal of the vehicle operator of the status of such elevation. For instance, it is desirable that some perceptive warning be available to the operator indicating that an antenna is in its fully elevated and, consequently, vulnerable orientation. Additionally, it is desirable that the operator have some positive indication that the antenna is in an appropriately secure location or orientation. In addition to such features, it is desirable that an automatic logic be incorporated with the antenna elevation scheme such that only one manual manipulation, the throwing of a single switch, serves to elevate the antenna automatically while energizing the vehicle mounted radio. Similarly, it is desirable that the antenna automatically be retracted upon turning off energy to the radio.
It reasonably may be anticipated that in the course of normal vehicle usage the operationally oriented antennae will sometimes strike overhead objects. On such occurences, it is important to minimize damage both to the antenna rod structure as well as to the mounting components from which it is supported. Accordingly, some form of override is desirable to permit movement of the antenna from its operational orientation without damage upon inadvertent encounters with overhead objects. Assuming such mounting features can be incorporated within the antenna support arrangement, it is further desirable that the elevating logic of the antenna erecting system be capable of automatically restoring a thus displaced antenna to its original operating position. With such an arrangement, slight displacements which may be caused by minor collisions in the course of driving would be automatically accommodated for by the antenna position control logic. Of course, such logic must be incorporated in a manner wherein the erecting device is fabricable utilizing high volume fabrication techniques suited to achieve those reasonable costs required in the consumer market.